The present invention relates to powder metallurgy and, in particular, to laminated metal-ceramic composite materials, which can be used for manufacture of some engineering parts of a high-temperature apparatus, specifically for thermal-protection linings, nozzles, combustion chambers, turbine blades and guide vanes of jet engines, crucibles, protection tubes of immersion thermometers for molten metals.
As it is well known, in different branches of industry there is a need for in principle new high-temperature (1500.div.2800.degree. C.) composites, which should be able to withstand extreme conditions of large mechanical loads, abrasive and oxidative influences, thermal shocks, etc.
In accordance with thermal and mechanical requirements the composites can be subdivided into the following groups:
Group 1: Composites, keeping for a long time in oxidizing media at a temperature up to 1500.div.1800.degree. C. an enough strength, impact resistance, hardness. The most important applications of the composites include turbine blades, guide vanes and combustion chamber lining of jet engines; PA1 Group 2: Composites, working at temperatures up to 2000.degree. C. and in a conditions of large thermal shocks, but are not exposed to serious mechanical loads. The most important applications of the composites include crucibles for high-temperature metals casting, protection tubes of immersion thermometers for molten metals; PA1 Group 3: Composites, working at a temperature up to 2500.div.2800.degree. C. in abrasive and oxidative high-speed gas fluxes, at moderate mechanical loads, but in conditions of large heat flows and thermal shocks. The most important applications of the composites include nozzles, combustion chambers, turbopump parts, thermal protection plates. PA1 refractory oxide, for example, such as alumina, yttia, zirconia or hafnia. PA1 an oxygen devoid compound, possessing increased high-temperature creep resistance, for example, zirconium carbide or hafnium carbide. PA1 a ductile component of refractory metal, for example, molybdenum or tungsten metal. PA1 The metallic tapes create, because of their plasticity, like in other multilayer structures with a metallic component, numerous barriers against cracks spreading and development, that provides a dramatic increase of a thermo- and crack-endurance; PA1 Because in the novel composite at least one component forms a continuum, it has increased, as compared with other laminated composites of equal chemical composition, strength, fracture toughness, wear resistance, erosion resistance and oxidation resistance; PA1 As a result of random arrangement of the multilayer band-shaped curved chips the novel composite structure is isotropic.
A number of composite material classes have been considered as potential candidates for these applications.
There are known metal-ceramic composites, which comprise a ceramic matrix and a powder or fibrous metallic inclusions. Thermal and crack endurance, fracture toughness of a such dispersion- or fibrous reinforced composites are insufficient for a majority of the above mentioned applications. With considerable advantages posses a metal-ceramic composites with a laminated structure which provides an increase of the above mentioned properties as a result of metallic component addition in the form of thin layers.
The characteristic feature of the laminated composites is the braking of cracks on ceramic-metal interfaces: a crack, arising in ceramic layer, canceling at approach to metallic layer mainly because of the layer larger ductility.
In this subgroup of composites are the best known a multilayer composites (FIG. 1A), which consist, in particular, of alternating metallic and oxide layers.
The manufacture methods of such composites are based on use of organo-ceramic and organo-metallic films, making from a pastes, suspensions, slurries, cements, mastics, containing metallic and oxide powders with different organic binders (U.S. Pat. No. 3,556,837, U.S. Pat. No. 4,929,295, U.S. Pat. No. 5,223,064, JP 4114981, SU 1089077).
Composites of the subgroup have usually a good thermal shock resistance, high heat-insulating properties, but at the same time they have a number of typical drawbacks: limited interlayer adhesion and, as a consequence, lower mechanical properties, poor abrasion and wear resistance, and, as it must be especially noted, with such composites there is a problem of complex shape forming.
In this subgroup of metal-ceramic composites with a laminated structure are known also composites with so called laminar-granular structure, comprising randomly arranged cube-like multilayer granules (FIG. 1B) (for example: The composite HfO.sub.2 /Mo, J. Space/Aeron., 1965, v.43, No. 4, p.54). Substantially more complex parts can be manufactured from such composites, than from above mentioned multilayer composites, but there are a lot of different imperfections at interfaces of the multilayer granules, that results in reduction of strength, abrasion resistance and other mechanical properties.